<b>Distance from the edge of forest fragments influence the abundance of aphidophagous hoverflies (Diptera: Syrphidae) in wheat fields

Abstract

This study aimed to evaluate the influence of the distance from the edge of native forests on the abundance of aphidophagous hoverflies in wheat fields. The study was conducted in four commercial fields in the North of Paraná State, Brazil, during the wheat crop season of 2009. Two transects were surveyed parallel to the edge of the forest at two distances: 25 ("near") and 525 meters ("far") from the edge. The abundance of hoverflies was compared using a χ 2 test (p ≤ 0.05). In total, 1,845 hoverflies adults were collected, which represented 15 species and three genera. The most abundant species was Allograpta exotica (60.43%), followed by Toxomerus dispar (17.78%) and Toxomerus watsoni (7.26%) (Diptera: Syrphidae). An important inference was that all fields showed a higher abundance of aphidophagous hoverflies closer to the edge of the forest (25 m) during the wheat tillering stage. The initial abundance of aphidophagous hoverflies in wheat fields is likely greater near the edge because of the availability of resources in the surrounding forest that enhance hoverfly survival during periods of low aphid infestation.

Conservation of hoverflies (Diptera, Syrphidae) requires complementary resources at the landscape and local scales

“…Our study showed that the distance to larval habitat, especially forests, was the main factor related to larval habitats that influenced hoverfly visitor composition. These results are consistent with other studies (Dupont & Nielsen, ; Meyer et al ., ; Bortolotto et al ., ) in which adult hoverflies were highly influenced by the types of larval macrohabitats, especially forest fragments, in the surrounding landscape. For an insect species to persist in a heathland fragment, larval and adult resources have to be available within the flight distance of the specific insect species.…”

The Hoverflies of an Oak Dehesa from Spain, with a New Species and Other Insights into the Taxonomy of theEumerus tricolorGroup (Diptera: Syrphidae)

“…S. scripta, E. balteatus, E. corollae) and move easily among different areas (Speight 2015) within the Iberian Peninsula. On the other hand, dehesas may act as prey reservoirs for predatory hoverflies of crops during periods of low infestation (Bortolotto et al 2016).…”

The effects of landscape structure and crop management on insect community and associated ecosystem services and disservices within coffee plantation

“…Here we provide empirical evidence that forest remnants are sources of natural enemies of a widespread and costly pest in coffee, and that the proportion of forest cover on the landscape increases biodiversity and ecosystem services in a Neotropical region. Similarly, previous studies conducted in Brazil found that forest remnants increase the abundance and diversity of beneficial insects including bees , syrphids , parasitoids (Bortolotto et al, 2016) and predatory wasps (Sousa et al, 2011) in adjacent agroecosystems. Thus, we recommend that agri-environment schemes in Brazilian agricultural landscapes should focus on the conservation of forest remnants and forest restoration in areas of low agricultural importance, abandoned crops and riparian areas at multiple spatial scales.…”